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SILURIAN TRILOBITES. 



Foreign Distribution. — I have figured (fig. 10 b) a Normandy specimen of the species. 

 It is from the May Sandstone of Caen (Mus. Geol. Society). 



HOMALONOTUS, Sp. PI. X, fig. 18. 



II sp. caudd lata brevi, profunde sulcata, axe angustiore, lateribus convexis curvis (nec 

 subplanis declivibus) ; sulcis lateralibus 6 — 7 profundis vix marginem granulatum attin- 

 gentibus, et ad apices paullulum interlineatis. 



There is some indication in Deslongschamps' figures, pi. xx, figs. 1, 2, of a distinct 

 species, with a squarer front to the head than in his H. Brongniarti, figured above. 

 But these indications are obscure : they certainly do not represent our second species, 

 for this has fewer and stronger, not more and fainter, ribs to the tail. 



The tail was broad when perfect, probably 2| inches by less than 1^ in length. Of 

 this width the axis can scarcely be one third, and it is well marked out and scored with 

 several rather deep furrows. The sides are convex, not steeply sloping off, and deeply 

 grooved by at least seven curved furrows, which do not quite reach the granular margin, 

 and are interlined near their tips. The facet is very broad and distinct, and the upper 

 furrow strongest, but not greatly so. 



This I do not name, for it is possibly a described foreign species. But it is clearly 

 not the //. Barrandei, of Rouault, a species with only four lateral ribs to the tail, and a 

 very strongly marked axis, which reaches the border. 



Localitg. — Budleigh Salterton (Mr. Vicary's cabinet). 



Homalonotus, sp. Woodcut, fig. 26. 



? H. bisulcatus, M'Coy. Quart. Journ. Geol. Soc, vol. viii, p. 13. 



Fig. 26. I figure here a small species, which, by its distinct ribs 



on the axis and sides, appears to differ from the others, 

 and which may possibly be the species catalogued by Prof. 

 M'Coy as II bisulcatus. It differs from that fossil in 

 several points ; having a greatly more arched anterior 

 margin, and strong ribs on the narrower axis, with 



Homalonotus, sp., Lower Silurian, . , ., .. „ , 



oorran Haven, Cornwall. numerous lateral ribs. We wait tor better specimens. 



Localitg. — Lower Silurian quartzites of Gorran 

 Haven, S. Cornwall; (cabinet of Mr. H. W. Edgell). These beds appear to me to be 

 identical with those which supplied the pebbles for the Budleigh Salterton bed above 

 referred to. They contain at least some of the same fossils. (See ' Geological Magazine 5 

 for July, 1864, vol. i, p. 9.) 



